Gérard Besson's Blog

Geometry, Geometric Analysis, Topology and other topics

New ERC advanced grant GEometry and Topology of Open Manifolds (GETOM)

leave a comment »

Starting February 1st I obtained an advanced grant from the European Research Council. The grant concerns the geometry and topology of open 3-manifolds. A web page will be ready soon. A one year post-doctoral position is now adertised. All informations are posted on

http://www-fourier.ujf-grenoble.fr/~besson/PostDoc-2013.pdf

Written by Gérard Besson

May 8, 2013 at 4:20 pm

Posted in Informations

Lecture by Luc Lemaire

leave a comment »

Professor Luc Lemaire from the Université Libre de Bruxelles gave a talk (in french) on the proof of the Poincaré conjecture for a large audience (high school students, teachers, etc…). The text of his lecture is available here.

Written by Gérard Besson

February 16, 2010 at 8:05 am

Post-Doctoral Positions

leave a comment »

The A.N.R. Grant named FOG (Flots et opérateurs géométriques) opens three six months post-doctoral positions in one of the partner departments to be held during the academic year 2010-2011. The applicants should be working on a subject related to the grant theme. The deadline for applications is May 1st and more informations are available here.

Written by Gérard Besson

February 6, 2010 at 10:00 am

Bourbaki goes to Luxembourg (garden)

leave a comment »

On march 15th, 2009, I gave the Bourbaki lecture on “the differentiable sphere theorem”. As a protest against the government policy, the beginning of the lecture has been given on the bandstand of Jardin du Luxembourg. After ten minutes we had to leave when the senate police arrived. We then finished the lecture in  the regular room at Institut Henri Poincaré. A video is posted on You Tube.

Written by Gérard Besson

January 9, 2010 at 9:31 am

The power of mathematics, why they still are unavoidable

leave a comment »

The magazine La Recherche recently published a special issue (Les Dossiers de La Recherche n°37 trimestriel novembre 2009). An improved  version of a previous paper appeared in this volume. It is entitled  “Comment on est venu à bout de la conjecture de Poincaré” and contains a wide-audience description of Perelman’s works on Hamilton’s Ricci flow leading to  the proof of Poincaré’s Conjecture. A previous version also published in La Recherche is available here.

Written by Gérard Besson

January 1, 2010 at 5:19 pm

Collapsing irreducible 3-manifolds with nontrivial fundamental group

leave a comment »

This is a joint work with Laurent Bessières, Michel Boileau, Sylvain Maillot and Joan Porti. Let M be a closed, orientable, irreducible, non-simply connected 3-manifold.We prove that if M admits a sequence of Riemannian metrics which volume-collapses and whose sectional curvature is locally controlled, then M is a graph manifold. This is the last step in Perelman’s proof of Thurston’s Geometrisation Conjecture.

The reference is:

L. Bessières, G. Besson, M. Boileau, S. Maillot and J. Porti Collapsing irreducible 3-manifolds with nontrivial fundamental group Invent math (2010) 179: 435–460.

Written by Gérard Besson

December 25, 2009 at 6:38 pm

Sciences Festival in Paris

leave a comment »

For the Sciences Festival in Paris, I gave a lecture  in Jussieu on Saturday, November 21st. The title was “La conjecture (résolue) de Poincaré : flots géométriques et applications”. I described the curve shortening process and its application to images denoising. After a description of the classification of orientable and closed surfaces, I stated the Poincaré conjecture. I then attempted an intuitive definition of the Ricci curvature and alluded to Hamilton’s Ricci flow.

Find here the lecture Beamer file.

Written by Gérard Besson

December 25, 2009 at 5:02 pm

Follow

Get every new post delivered to your Inbox.